The halo — also known as a “moon rainbow” or “moonbow” — appeared around 11:30 p.m., to the delight of local Twitter and Facebook users, who quickly started asking questions like, “How does a #moonbow even happen?”
Well, according to the Ask an Astronomer blog from Cornell University, moonbows are caused by the light of the moon passing through a thin layer of ice crystals in the upper atmosphere. The crystals refract the moonlight the way water droplets refract sunlight to produce a rainbow.
On the heels of the moonbow, the Hunter’s Moon will make an appearance over D.C. tonight. According to the Farmer’s Almanac, the Hunter’s Moon, also called the Blood Moon, is the smallest full moon of the year and should be at its fullest shortly after 10 p.m. Fingers crossed that the rain clouds hold off until then.
Did you see the #moonbow? Tell us about it in the comments below.